This invention relates to a polycyanoaryl ether stretched or oriented film or fiber having superior heat resistance and mechanical strength.
For electrical and electronic equipments, there have been widely employed films of those resins having superior heat resistance, mechanical strength or electric properties. Recently, as such equipments have been much more miniaturized and lightened, there is a need for more superior heat resistance and mechanical strength on the film materials to be applied. In order to meet such a need, stretched films of, e.g., aromatic polyesters have been hitherto employed in the art. However, such aromatic polyester oriented films would not be said to fully satisfy the above-depicted need as industrial films. Therefore, there is a need for a film with far higher heat resistance and mechanical strength.
On the other hand, as application of various plastic materials has been recently broadened, there has become more serve a demand for properties of such materials, e.g., heat resistance or mechanical strength. Thus, it has been generally done to add a reinforcing fiber into plastic materials for providing a higher mechanical strength. As the reinforcing fiber, there have been employed a wide variety of fibers composed of, e.g., any inorganic material or synthetic resin. However, those inorganic fibers are difficult to be produced in a large scale and at a low cost owing to many steps required for the manufacture thereof, while those synthetic resin fibers present the problem that heat resistance and mechanical strength of the fiber itself are not necessarily satisfactory, though manufactured readily. Therefore, there is also a need for a reinforcing fiber composed of a synthetic resin with far higher heat resistance and mechanical strength.